A blanket is a piece of cloth that you use to keep warm or to sit upon.
My dogs go on the blanket.

down
They fly up and down!

to move, travel, or proceed
My cats go on their pillows.

a conventional expression of farewell used in the late afternoon, the evening, or at night, esp when departing to bed
My rabbit goes in the bed. "Good night, rabbit!"

pillow
My cats go on their pillows.

the large, bright, burning object in space which Earth circles around
The sun goes down.